Step by step, things are clearly coming up through the hard work, regular reports by Elrond, the mainnet will arrive in Q4 2019.
This is the ElrondNetwork # 10 report, specifically from Adrian Dobrita, a key member of the Elrond team. You can read the details through this Twitter link:
Website: https://elrond.com/
Telegram: https://t.me/ElrondNetwork
Tele Ann: https://t.me/ElrondNetworkAnn
Elrond Community: https://community.elrond.com